Thats a nice first up effort, your painting is quite good, when I started not all that long ago I'd end up with the wrong coloured paint in the wrong sections because of my unsteady hands.

While the idea of Nemesis prime might not be original, I quite like the look of the brighter blue with the black on the Animated mold, its visually striking.

When you are painting a darker shade of paint on a lighter coloured plastic, you don't need to undercoat. However if you are painting a lighter shade on dark plastic then I suggest getting a spray can of White Undercoat, it will make your job much easier.